It should take under a minute to start up; with your large library maybe a bit longer, but not 25. This happened to me once too but I didn't find the root cause; seemed to be related to subtitle import.The next version will bring possibilities to group stuff like tv series.

If you always wanted to have your most recent videos at the top of the folder in the ps3 or wished you could group all videos with the same genre in one folder, have a look at pms-mlx